JP2013046937A - Object gripping apparatus, object gripping method, and object gripping program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an object gripping apparatus that can identify an intended gripping position, and can appropriately grip an object.SOLUTION: In this object gripping apparatus, an operation of a gripped part 1 is controlled so as to grip the gripping position 104 of the gripped object 100 based on a three-dimensional position and an attitude of the gripped object 100 and the gripping position 104 that is preliminarily set at each gripped object 100.

Description

  The present invention relates to an object gripping device, an object gripping method, and an object gripping program, and more particularly to operation control of a hand unit provided in a robot.

  2. Description of the Related Art Conventionally, a method for handling a robot's hand unit by recognizing a target three-dimensionally and targeting a three-dimensional position of the recognized target is performed.

  Patent Document 1 discloses a method for performing assembly work by a robot using three-dimensional CAD (Computer Aided Design) data. Specifically, the assembly work is performed by teaching, and the position to be gripped by the hand portion of the robot is set at the time of assembly.

  Patent Document 2 discloses a method for improving workability by creating an assembly work sequence.

JP 2006-350620 A JP 2008-46924 A

  In the method described in Patent Document 1, in order to actually hold an object with the hand unit, it is necessary to simulate the degree of adaptation of the shape of the hand unit with respect to the shape of the recognition target and handle the hand unit. is there.

  At this time, the positional relationship of the hand unit with respect to the recognition target object identified by the simulation, that is, the position where the recognition target object is gripped by the hand unit is the same as intended when designing the parts as the recognition target object. It may not be. There is a case where the position of a part or the like that is supposed to be gripped at the time of design is different from the gripping position specified by the simulation, and as a result, there is a problem that the work is not appropriately performed.

  In addition, even when a product is manufactured by combining parts as recognition objects, the gripping position that is intended to be effective for the combination may not be identified by simulation, and as a result the intended assembly There was a case where the state could not be realized.

  The present invention has been made to solve the above-described problems, and provides an object gripping apparatus that can specify an intended gripping position and appropriately grip an object, and a method and program thereof. With the goal.

  The object gripping apparatus according to the first aspect of the present invention includes a gripping unit that grips a gripping target and a control unit that controls the operation of the gripping unit, and the control unit is configured to provide a three-dimensional position of the gripping target. The operation of the gripping unit is controlled so as to grip the gripping position of the gripping object based on the posture and the gripping position preset for each gripping object.

  The invention of claim 2 is the object gripping apparatus according to claim 1, further comprising an imaging unit that captures a parallax image of the gripping object, and information on the three-dimensional position and orientation of the gripping object. Is generated based on the parallax image captured by the imaging unit.

  The invention of claim 3 is the object gripping device according to claim 2, wherein the information of the three-dimensional position and orientation of the gripping object is prepared in advance for each gripping object, And generated by matching with the parallax image captured by the imaging unit.

  A fourth aspect of the present invention is the object gripping device according to the third aspect, wherein the information on the gripping position is added to the three-dimensional model.

  A fifth aspect of the present invention is the object gripping device according to any one of the second to fourth aspects, wherein the imaging unit is attached to the gripping unit.

  A sixth aspect of the present invention is the object gripping apparatus according to any one of the first to fifth aspects, wherein one or a plurality of the gripping positions are set for each gripping target object.

  The invention according to claim 7 is the object gripping apparatus according to claim 6, wherein the control unit is configured to select at least one of the plurality of gripping positions set according to the three-dimensional posture of the gripping object. One is selected.

  The invention of claim 8 is the object gripping device according to any one of claims 1 to 7, wherein the information on the gripping position includes information on an approach angle of the gripping part with respect to the gripping position. It is characterized by.

  The invention of claim 9 is the object gripping apparatus according to any one of claims 1 to 8, wherein when the plurality of gripping objects are combined with each other, the gripping position is such that each gripping object is mutually It is characterized in that it is set in advance so as to avoid the contact portion that contacts.

  The invention of claim 10 is the object gripping device according to claim 9, wherein the information on the gripping position includes information on an approaching angle of the gripping part with respect to the gripping position, and the approaching angle is The three-dimensional position of the grip part is an approach angle that is a three-dimensional position that does not cover the contact part.

  The invention of claim 11 is a method for gripping an object, wherein (a) a step of acquiring information on a three-dimensional position and posture of the gripping object, and (b) preset for each gripping object. A step of acquiring information on a gripping position; and (c) an operation of the gripping unit to grip the gripping position based on the three-dimensional position and posture of the gripping target object and the gripping position of the gripping target object. And a step of controlling.

  The invention of claim 12 is an object gripping program, and is installed in a computer and executed, whereby the apparatus for controlling the gripping part by the computer is described in any of claims 1 to 10. It functions as an object gripping device.

  According to the first to tenth aspects of the present invention, the intended gripping position is specified by controlling the operation of the gripping part so as to grip the gripping position set in advance of the gripping target, and the gripping target is appropriately handled. Can be gripped.

  In particular, according to the sixth to eighth aspects of the present invention, the gripping position includes information on the approach angle, and one or a plurality of gripping positions are set for each gripping object and selected according to a three-dimensional posture. A gripping position suitable for each state of the object can be selected.

  Particularly, according to the ninth and tenth aspects of the present invention, the information on the approaching angle of the gripping part is included in the information on the gripping position set in advance so as to avoid the contact part, and the approaching angle is determined by the gripping part being the contact part. It is possible to control the three-dimensional position and posture of the gripping part during the combination operation, and the gripping part does not become an obstacle when combining the gripping objects. Combination operations can be performed appropriately.

It is the figure which showed notionally the structure of the target object gripping apparatus concerning 1st Embodiment. It is a figure which shows the example of the hardware structure of the target object holding | grip apparatus concerning 1st Embodiment. It is a flowchart which shows operation | movement of the target object gripping apparatus concerning 1st Embodiment. It is a figure explaining operation | movement of the target object gripping apparatus concerning 1st Embodiment. It is the figure which showed notionally the structure of the target object gripping apparatus concerning 2nd Embodiment. It is a figure which shows the example of the hardware structure of the target object holding | grip apparatus concerning 2nd Embodiment. It is a flowchart which shows operation | movement of the target object gripping apparatus concerning 2nd Embodiment. It is a figure explaining operation | movement of the target object gripping apparatus concerning 2nd Embodiment.

<A. First Embodiment>
<A-1. Configuration>
FIG. 1 is a diagram conceptually showing the configuration of the object gripping apparatus according to the present embodiment. As shown in FIG. 1, an object gripping apparatus according to the present invention includes a gripping unit 1 (for example, a robot hand unit) that grips a gripping target 100 and a control unit 2 that controls the operation of the gripping unit 1.

  Further, as shown in FIG. 1, an imaging unit 3 can be provided in order to recognize the three-dimensional position and posture of the grasped object 100.

  For example, when the imaging unit 3 such as a stereo camera is provided, the parallax image of the gripping object 100 captured by the imaging unit 3 is used to perform matching with the three-dimensional model of the gripping object 100 prepared in advance. The three-dimensional position and orientation of the object 100 can be obtained. The imaging unit 3 can also be attached to the grip unit 1. Specifically, when the gripping unit 1 is a robot hand unit, the gripping target object 100 can be captured from a viewpoint closer to the gripping target object 100 by being attached to the base portion of the hand unit (see FIG. 2). It is possible to recognize the three-dimensional position and posture with higher accuracy.

  Even if the imaging unit 3 is not provided, it is sufficient that the three-dimensional position and orientation of the grasped object 100 can be measured from a sensor or the like, and the measurement result may be given to the control unit 2 from the outside. Good.

  FIG. 2 shows an example of the hardware structure of the object gripping apparatus according to this embodiment.

  As illustrated in FIG. 2, the object gripping apparatus includes a gripping unit 1 (corresponding to the robot hand unit 1R and the hand unit 1L) that grips the gripping object 100 (for example, a component) and a three-dimensional position of the gripping target object 100 And an imaging unit 3 for recognizing the posture (corresponding to the camera 102 attached to the hand unit) and a control unit 2 (corresponding to the CPU 103) for controlling the operation of the gripping unit 1.

  In FIG. 2, a double-arm robot is shown as the object gripping device, but a single-arm robot may be used. Further, the shape of the gripping object 100 is not limited to the illustrated one.

<A-2. Operation>
Next, operation | movement by the control part 2 of the target object gripping apparatus concerning this embodiment is demonstrated using FIG. 3 and FIG.

  First, a parallax image of the grasped object 100 is obtained using the camera 102 (step S1). Here, when recognizing the three-dimensional position and posture of the grasped object 100 regardless of image matching, the operation can be omitted.

  Next, three-dimensional matching is performed using the three-dimensional model prepared or measured in advance with respect to the grasped object 100 and the parallax image (step S2). Here, the three-dimensional model indicates a set of point groups each having three-dimensional coordinate information, and includes three-dimensional coordinate information corresponding to each side, each vertex, and the like of the grasped object 100. The three-dimensional model is stored in a predetermined storage unit or the like, and is read and used when performing three-dimensional matching. The three-dimensional position and posture of the grasped object 100 can be recognized by the three-dimensional matching.

  Next, information on the grip position of the grip target 100 that is set in advance is acquired (step S3), and the grip position in the three-dimensional position and posture of the grip target 100 is specified.

  The grip position information is set as shown in FIGS. 4A to 4C, for example, and is information that specifies in advance for each grip target 100 the position to be gripped by the hand unit 1R. Specifically, it is text data of three-dimensional coordinate information indicating the grip position 104 described in a local coordinate system fixed for each grip object 100. In controlling the operation of the hand unit 1R, it is used after being converted into the coordinate system of the robot.

  A plurality of gripping positions 104 can be set according to the state of the hand unit 1R (the shape and size of the hand unit, the number of fingers, the position of the center of gravity, etc.), the strength of the gripping object 100 at the position gripped by the hand unit 1R, and the like. it can. For example, as shown in FIGS. 4A and 4B, when the three-dimensional posture of the object to be grasped 100 is the same, it is possible to select a suitable grasping position 104 according to the state of the hand unit 1R. It is. Specifically, the selection can be made in consideration of, for example, the operating range of the finger, the gripping force at the time of gripping, the position interval of the gripping position relative to the gripping force, the gripping force resistance, and the like. The selection may be performed at the present time, or may be performed after the hand unit 1R has moved to the vicinity of the three-dimensional position of the grasped object 100.

  In the case shown in FIG. 4A, the gripping operation of the hand unit 1R is controlled so that the gripping position 104 corresponds to the central three-dimensional position of the hand unit 1R. In the case shown in FIG. The gripping operation of the hand unit 1R is controlled so that the position 104 corresponds to the position of each finger of the hand unit 1R. Further, as shown in FIG. 4C, the gripping positions 104 can be increased to three or more points according to the number of fingers.

  The grip position information can include angle information when the hand unit 1R enters the grip position 104 in addition to the grip position information. The angle information is angle (direction) data described in a local coordinate system fixed for each gripping object 100, and is used after being converted into a robot coordinate system when controlling the operation of the hand unit 1R. Based on the angle information, the three-dimensional position and posture of the hand unit 1R when the hand unit 1R performs a gripping operation can be controlled.

  A plurality of gripping positions 104 set for the gripping target object 100 can be set in correspondence with what three-dimensional posture the gripping target object 100 is placed. By setting in this way, it is possible to select at least one appropriate gripping position 104 for the gripping object 100 having different three-dimensional postures and use it for the gripping operation. Specifically, a gripping position that does not change the three-dimensional posture of the gripping object 100 as much as possible (for example, a surface and a side excluding a vertically downward surface when the gripping object 100 is placed) is selected. Or, conversely, a gripping position for changing to a desired three-dimensional posture can be selected. The selection may be performed at the present time, or may be performed after the hand unit 1R has moved to the vicinity of the three-dimensional position of the grasped object 100.

  This gripping position information is preferably added in advance to the three-dimensional model of the gripping object 100, but is stored in advance in another storage unit or the like, and is given to the control unit 2 during a gripping operation. Also good. In addition, when adding to a three-dimensional model beforehand, it is desirable to add to the three-dimensional CAD data of each gripping object 100 at the stage of creating the three-dimensional model. If gripping position information is added in this way, a position suitable for gripping that is assumed for each gripping object at the time of design can be specified at the time of the gripping operation, and the feasibility of the intended gripping operation is increased. .

  Next, the control unit 2 moves the hand unit 1R based on the three-dimensional position and posture of the gripping object 100, and also the gripping position 104 (Step S4), and causes the hand part 1R to grip the gripping position 104 of the gripping object 100. Is gripped (step S5).

  When gripping, it is possible to perform the gripping operation while confirming whether or not the gripping position 104 indicated by the gripping position information is properly gripped using the camera 102 provided in the hand unit 1R. When the grip position to be gripped by the hand unit 1R is one point, the gripping operation may be performed by aligning the one point with the center of the imaging region of the camera 102 (in this case, the grip position is the center of the grip unit 1). It is set corresponding to the three-dimensional position). When there are two gripping positions to be gripped by the hand unit 1R, the gripping operation may be performed by aligning the center positions of the two points with the center of the imaging region of the camera 102.

<A-3. Effect>
According to the embodiment of the present invention, in the object gripping apparatus, the gripping object 100 is based on the three-dimensional position and posture of the gripping object 100 and the gripping position 104 set in advance for each gripping object 100. By controlling the operation of the gripper 1 so as to grip the gripping position 104, the intended gripping position 104 can be specified and the gripping object 100 can be gripped appropriately.

  In addition, it is not necessary to perform a simulation of the shape of the grasped object 100 and the shape of the hand portion 1R and confirm the positional relationship, thereby facilitating operation control.

  In addition, according to the embodiment of the present invention, in the object gripping apparatus, the information on the gripping position 104 is added to the three-dimensional model of the gripping object 100, and is assumed for each gripping object at the time of design. The position to be grasped can be set in advance, and the work can be performed while grasping the intended part.

  Further, according to the embodiment of the present invention, in the object gripping apparatus, one or a plurality of gripping positions 104 are set for each gripping object 100, so that appropriate gripping can be performed according to the state of the hand unit 1R. The position 104 can be selected.

  Further, according to the embodiment of the present invention, in the object gripping device, the control unit 2 selects at least one of the plurality of gripping positions 104 set according to the three-dimensional posture of the gripping object 100. By doing so, it is possible to select a gripping position suitable for each state of the gripping object 100.

  Further, according to the embodiment of the present invention, in the object gripping apparatus, the information on the gripping position 104 includes the information on the approach angle of the gripping unit 1 with respect to the gripping position 104, so that the hand unit during the gripping operation can be obtained. It is possible to control the three-dimensional position and orientation of 1R, and it is possible to realize a gripping operation more in line with the intention.

<B. Second Embodiment>
<B-1. Configuration>
FIG. 5 is a diagram conceptually showing the configuration of the object gripping apparatus according to the present embodiment. As shown in FIG. 5, the gripping unit 1, the control unit 2, and the imaging unit 3 are provided as in the first embodiment, but differ in that a plurality of gripping objects 100 and gripping objects 101 are gripped. In FIG. 5, two gripping objects are illustrated, but the number is not limited to two and may be plural.

  FIG. 6 shows an example of the hardware structure of the object gripping apparatus according to this embodiment.

  As shown in FIG. 6, the object gripping device includes a gripping unit 1 that grips a gripping target object 100 (for example, a component) and a gripping target object 101 (for example, a component) (corresponding to the robot hand unit 1R and the hand unit 1L). An imaging unit 3 (corresponding to the camera 102 provided in the hand unit) for recognizing the three-dimensional positions and postures of the gripping object 100 and the gripping object 101, and a control unit 2 for controlling the operation of the gripping part 1. (Corresponding to the CPU 103). Here, the gripping object 100 and the gripping object 101 are components that can be combined with each other.

  The object gripping apparatus shown in FIG. 6 can grip at least one of the gripping object 100 and the gripping object 101 and perform the work in combination with the other gripping object.

<B-2. Operation>
Next, operation | movement by the control part 2 of the target object gripping apparatus concerning this embodiment is demonstrated using FIG. 7 and FIG.

  First, a parallax image of the grasped object 100 is obtained using the camera 102 (step S11). Next, three-dimensional matching is performed using the three-dimensional model measured in advance with respect to the grasped object 100 and the parallax image (step S12). The three-dimensional position and posture of the grasped object 100 can be recognized by the three-dimensional matching.

  Next, information on a gripping position of the gripping target object 100 and contact portion information described later are acquired (step S13), and the gripping position in the three-dimensional position and posture of the gripping target object 100 is specified.

  Here, for example, as shown in FIGS. 8A and 8B, the gripping position is determined based on the contact part information that is information about the surface and the side that are in contact with each other, that is, the contact part a. It is set so as to avoid the part a. Also, the information on the approach angle when the hand unit 1R enters the grip position 104, which is included in the grip position information, is an entry angle at which the hand unit 1R grips the grip position 104 at an approach angle that does not cover the contact part a. Can be set to

  The acquired contact part information is preferably added in advance to the three-dimensional model of the gripping object 100 and the gripping object 101 as in the case of the gripping position information, but is stored in advance in another storage unit or the like, It may be given to the control unit 2 at that time. In addition, when it is added to the 3D model in advance, it is added to the 3D CAD data of each gripping object and associated with a BOM (Bill of Materials) in the stage of creating the 3D model. It is desirable.

  The contact portion information may be set with a plurality of patterns corresponding to the combination methods of the gripping objects. In other words, FIG. 8 shows a plurality of gripping positions 104 set for the common contact part a, but when another contact part a is set, a new gripping position 104 is set in advance. be able to.

  Next, the control unit 2 moves the hand unit 1R based on the three-dimensional position and posture of the gripping target object 100, the gripping position, and the like (step S14), and sets the gripping position of the gripping target object 100 to the hand part 1R. Grip (step S15). Here, the object to be grasped may be the object to be grasped 101. In that case, the above operation is performed on the grasped object 101.

  Next, the gripping object 100 (or the gripping object) is so arranged that the contact part of the gripping object 100 (or the gripping object 101) comes into contact with the contact part of the other gripping object 101 (or the gripping object 100). The three-dimensional position and posture of the object 101) are matched, and the gripping object 101 and the gripping object 100 are combined (step S16).

<B-3. Effect>
According to the embodiment of the present invention, in the object gripping apparatus, the gripping position 104 is set in advance so as to avoid the contact portion a where the gripping object 100 and the gripping object 101 are in contact with each other. When combining each other, the hand unit 1R does not become an obstacle to the operation, and the combination operation can be performed appropriately.

  Further, according to the embodiment of the present invention, in the object gripping apparatus, the information on the gripping position 104 includes information on the approach angle of the gripper 1 with respect to the gripping position 104, and the approach angle is determined by the gripper 1. Since the approach angle does not cover the contact portion a, it is possible to control the three-dimensional position and posture of the hand unit 1R during the combination operation, and the operation control of the hand unit 1R can be performed without hindering the combination operation. it can.

  In addition, since the gripping position can be easily specified without relying on teaching, it is easy to create a program that requires complex assembly when the number of parts is large.

  It can be used for assembling parts or devices using a robot.

DESCRIPTION OF SYMBOLS 1 Grip part 1L, 1R Hand part 2 Control part 3 Imaging part 100, 101 Grasping object 102 Camera 104 Gripping position

Claims (12)

A gripping part for gripping the gripping object;
A control unit for controlling the operation of the gripping unit,
The control unit is configured to hold the gripping position of the gripping object based on a three-dimensional position and posture of the gripping object and a gripping position set in advance for each gripping object. Controlling the operation,
Object gripping device. An imaging unit that captures a parallax image of the grasped object;
The information on the three-dimensional position and orientation of the grasped object is generated based on the parallax image captured by the imaging unit.
The object gripping apparatus according to claim 1. The information on the three-dimensional position and orientation of the gripping object is generated by matching a three-dimensional model prepared for each gripping object in advance with the parallax image captured by the imaging unit. To
The object gripping device according to claim 2. The grip position information is added to the three-dimensional model.
The object gripping device according to claim 3. The imaging unit is attached to the gripping unit,
The object gripping device according to any one of claims 2 to 4. The gripping position is set to one or more for each gripping object,
The object gripping device according to any one of claims 1 to 5. The control unit selects at least one of the plurality of gripping positions set according to the three-dimensional posture of the gripping object,
The object gripping device according to claim 6. The information on the grip position includes information on an approach angle of the grip portion with respect to the grip position,
The object gripping device according to any one of claims 1 to 7. When combining a plurality of the gripping objects with each other,
The gripping position is set in advance so as to avoid contact portions where the gripping objects contact each other,
The object gripping device according to claim 1. The information on the grip position includes information on the angle of approach of the grip portion with respect to the grip position,
The entry angle is an entry angle at which the three-dimensional position of the grip portion is a three-dimensional position that does not cover the contact portion.
The object gripping device according to claim 9. A method of causing the gripping unit to grip a gripping object by controlling a predetermined gripping unit having a gripping mechanism by a predetermined control unit,
(A) obtaining information on a three-dimensional position and posture of the grasped object;
(B) obtaining information on a grip position set in advance for each gripping object;
(C) including a step of controlling the operation of the gripping unit by the control unit so as to grip the gripping position based on the three-dimensional position and posture of the gripping target and the gripping position of the gripping target. Characterized by the
Object gripping method. The apparatus that controls the gripping unit by the computer by being installed in a computer and executed is caused to function as the object gripping device according to any one of claims 1 to 10.
Object gripping program.

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